Welcome to the software list! This is by no means a complete list of everything that exists, but is a focused list of useful software for AMV editors. This list is an optimized and updated version of the original software list thread created by TaranT. If you have any recommendations for this list, feel free to post them in this thread with as much information as you can!

FFmpeg's support of AviSynth scripts is multiplatform, but the usefulness of it on Linux and OSX is questionable because it uses AvxSynth to do it there, and the usefulness of AvxSynth is questionable because of the near-total lack of plugins. But it does work if the script does. The proper FFmpeg builds that Debian and Ubuntu now ship in their repositories have AviSynth script support enabled, only requiring the user to actually install AvxSynth (which they can do from a PPA if they don't want to build from source). x264 can also use AvxSynth on OSX and Linux.

More importantly, if/when AviSynth+ actually does rise from its current inactive period and finalize its non-Windows support, it's going to be a very trivial matter to get it working with FFmpeg on those platforms (literally just changing the library name given to dlopen, although all the ifdeffery needed for AvxSynth would also be removed).

Considering the "lack of plugins", it is much simpler to just say "Windows Only" since that would make it very useless in most cases and explaining all that takes a paragraph. That said, I was not aware AviSynth+ was working on non-windows support, so as soon as that is finished I will update the list!

l33tmeatwad wrote:Considering the "lack of plugins", it is much simpler to just say "Windows Only" since that would make it very useless in most cases and explaining all that takes a paragraph. That said, I was not aware AviSynth+ was working on non-windows support, so as soon as that is finished I will update the list!

Like avsplus development in general, it happens in fits and starts. innocenat had some introductory commits toward that end, and I'd attempted to split the compiler intrinsics because GCC's handling of them is braindead* (but I got sidetracked by other things and haven't had the energy to get back to it; there are more commits I have locally but they're a mess and it doesn't advance significantly enough beyond what's already there). Once those parts are all smoothed out, and it's certain that there's no miscompiling happening, my guess is that we'd be nearly there, although the plugin loader may need to be rewritten again.

*read: because GCC doesn't like having all the intrinsics in a single file, it would mean that - if the code was left as-is - you'd have to be running on at least Nehalem, and it also means no AVX or AVX2 intrinsics could be added because then it wouldn't even run on Nehalem (and there's no way around this, because the compiler flag to allow the intrinsics would cause crashes on any processor too old for the newest set to run, and even apply to the non-intrinsics code - you either turn them all off and can run it on everything, slowly, or turn them all on and cut out anything but the newest CPUs). MSVC compartmentalizes intrinsics so that you just don't get the higher-optimized versions if the CPU doesn't have the required SIMD available. To do that with GCC, the support for specific instruction sets have to be in separate files and the compiler flags divvied up on a 1:1 basis for the correct instruction set/file combination - which, while it makes a certain amount of sense from an academic 'best practices' point of view, is a PITA to implement in a build system (or worse, to retroactively fix for projects that up to that point, dumped all intrinsics into a single file).

On the free video editing software side, there is 3D blender which is cross platform and very powerful, thought the learning curve is steep.
Also, for Linux, there is LIVES which is quite powerful.
I am ignoring the 'Windows movie maker' single track clones which abound in Linux!